#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int mainl()
{
	int i = 0, j = 0;
	char a[20];
	char b;
	gets(a);
	for (;a[i]!='\0'; i++)
	{
		for (j = i+1; a[j] != '\0' ; j++)
		{
			b = a[i] <= a[j] ? a[i] : a[j];
			a[j]= a[i] >= a[j] ? a[i] : a[j];
			a[i] = b;
		}
	}
	printf("\n%s\n",a);
	return 0;
}